The present invention relates to a system in which outer lifting cords are eliminated from shades or blinds. More specifically, the present invention relates to window covering systems that employ one or more springs to accumulate the lifting cord within the head rail and/or bottom rail as the blind or shade is raised or lowered and a brake to secure the bottom rail in a static position.
It is generally known to provide for a window covering venetian blind with the slats that are raised and lowered by a pair of lift cords. Such known window coverings typically include lift cords that are secured to a bottom rail and extend upward through the slats into a head rail. The lift cords are guided within the head rail and exit through a cord lock and hang outside of the window covering. In order to raise or lower the window covering, the lift cords are manipulated to first release the cord lock. Similarly, once the window covering has been raised or lowered the cord lock is manipulated again to lock the cords in place. However, such an arrangement may present a safety concern to small children and pets.
Blinds and shades in which the lift cords are contained within the bottom rail, window covering and head rail are referred to as xe2x80x9ccordlessxe2x80x9d blinds and shades because no portion of the lift cords is external to the blind or shade. Cordless blinds have been gaining popularity and are employed in a wide variety of blinds and shades such as venetian blinds, cellular blinds, pleated shades, and wood blinds.
One way to provide a xe2x80x9ccordlessxe2x80x9d blind is to xe2x80x9cbalancexe2x80x9d the window blind system. In a xe2x80x9cbalancedxe2x80x9d cordless blind, the spring force of the spring motor is balanced by the combined weight of the bottom rail (and any accumulated window covering) and friction, sometimes misidentified in the field as inertia. In such balanced systems the friction is greater than the difference between the spring force and the combined weight of the bottom rail and accumulated window covering when the bottom rail is at any location between a fully extended position and a fully retracted position. However, such known cordless blinds have several disadvantages for a mass-merchandise avenue of distribution, including friction systems that are costly to assemble and manufacture, and difficult to incorporate in to size-in-store adjustment.
Another way to provide a xe2x80x9ccordlessxe2x80x9d blind is to include a brake that is configured to clamp onto one or more of the lift cords or engages the spring motor. One such known blind is shown in U.S. Pat. No. 6,029,734, and shows a venetian blind having a spring retrieving unit and spindle in a head rail, and a cord brake mechanism in a bottom rail. However, because the cord brake mechanism is located in the bottom rail while the spring motor is in the head rail and the lift cords connect the bottom rail to the head rail, it is only useful to prevent the bottom rail from free falling. As such, the spring retrieving unit must be weak so that the bottom rail does not creep upward. Also, opening of blind requires the user to exert effort to lift bottom rail and patience to wait for the weak spring retrieving units to wind up the slack cords.
Accordingly, it would be advantageous to provide a window covering with a strong spring motor that is configured to bias the bottom rail upward and capable of raising bottom rail absent a brake. It would also be advantageous to provide a cordless window covering with a cord brake that prevents the bottom rail from moving up or down.
A brake system that overcomes the disadvantages of the more complex and cumbersome systems of the prior art would represent a significant advance in this art.
How these and other advantages and features of the present invention accomplished (individually, collectively, or in various subcombinations) will be described in the following detailed description of the preferred and other exemplary embodiments, taken in conjunction with the FIGURES. Generally, however, they are accomplished in a window covering including a head rail, a bottom rail, a window covering material extending between the head rail and bottom rail, first and second lift cords extending between the head rail and the bottom rail, a biasing element such as a spring motor, and a brake. The spring motor is configured to bias the bottom rail toward the head rail, is mounted in the bottom rail, and is operatively coupled to the first and second lift cords. The brake is mounted in the bottom rail and configured to releasably couple to the first lift cord to prohibit the spring motor from taking up the first cord, which prohibits the bottom rail from being raised or lowered. The brake can include a one-way tensioning mechanism and a user interface. The one-way tensioning mechanism is configured to provide a resistant force on movement of the first lift cord. The user interface is configured to move the one-way tensioning mechanism between a stopped condition and a free-wheeling condition.
These and other advantages and features of the present invention may also be accomplished in a window covering mounted in a window frame. The blind includes a head rail, a bottom rail, a window covering material extending between the head rail and bottom rail, at least one lift cord extending between the head rail and the bottom rail, a first spring motor operatively coupled to the at least one lift cord and configured to bias the bottom rail toward the head rail, a first guide cord having a first end coupled to the window frame and at least partially located in the bottom rail, and a brake mounted in the bottom rail. The brake is configured to releasably couple to the first guide cord to prohibit the first guide cord from sliding through the brake, prohibiting the bottom rail from being raised or lowered.
These and other advantages and features of the present invention may also be accomplished in a window covering including a head rail mounted to a bracket, a bottom rail, a window covering material extending between the head rail and bottom rail, at least one lift cord extending between the head rail and the bottom rail, a spring motor mounted to the bracket, operatively coupled to the at least one lift cord, and configured to bias the bottom rail toward the head rail, and a brake directly coupled to the spring motor and configured to selectively prohibit the bottom rail from being raised and lowered.
These and other advantages and features of the present invention may also be accomplished in a window covering including a head rail, a bottom rail, a window covering material extending between the head rail and bottom rail, a pair of lift cords extending between the head rail and bottom rail, a spring motor, a brake, and a remote user interface. The spring motor is mounted in the head rail and is configured to bias the bottom rail toward the head rail. The brake is configured to selectively prohibit winding or unwinding of the lift cords from the spring motor. The remote user interface is coupled to the brake for selectively operating the brake without having to reach the head rail.
These and other advantages and features of the present invention may also be accomplished in a window covering comprising a head rail, a bottom rail, a window covering material extending between the head rail and bottom rail, first and second lift cords extending between the head rail and the bottom rail, a biasing element configured to bias the bottom rail toward the head rail, and operatively coupled to the first and second lift cords, and a brake assembly configured to inhibit movement of the bottom rail. The brake assembly includes a brake releasably coupled to the biasing element, a brake lever pivotally coupled to the bottom rail, and a user interface operatively coupled to the brake lever and configured to pivot it to a first position wherein the brake is in an engaged position and a second position wherein the brake is in a disengaged position.
The present invention further relates to various features and combinations of features shown and described in the disclosed embodiments. Other ways in which the objects and features of the disclosed embodiments are accomplished will be described in the following specification or will become apparent to those skilled in the art after they have read this specification. Such other ways are deemed to fall within the scope of the disclosed embodiments if they fall within the scope of the claims which follow.